I was (voluntarily) homeless in San Francisco for a while (http://austenallred.com/voluntarily-homeless-in-silicon-vall...), only because I wanted to work on my company instead of get a job, and I had read enough Thoreau that I didn't care to give up the majority of my time in exchange for crap I don't need. So I could have gotten a job, but I deemed it not worth giving up my freedom for. Of course, that came with other sacrifices, but I considered it worth it at the time.
In doing so, I ended up hanging out with a wide, wide variety of homeless people. Some were punk kids who wanted to reject society/capitalism, many of whom were from broken homes. Some were mentally handicapped. Some had done enough of some sort of drug that they were completely fried. A few seemed very intelligent - one lost his job as a physics professor when he had sex with one of his students, and his family was so ashamed they wouldn't take him in.
Saying things like "homelessness is a choice" is true for some subset of people, but completely untrue for others. Most of the homeless I hung out with were very affluent and had iPhones and MacBooks (you don't find many forced homeless pitching VCs in Palo Alto), but when I was in the city it was a different story. More mental handicaps, more felons, and more people who had simply fallen upon difficult times.
The amount of willingness they had in the matter is a spectrum., as was the tech they used, the reason they were homeless, and their ages But they're all people, and most of them that I met were good people, with wants and dreams and desires mostly just like everybody else. Please don't try to say, "All homeless people are x."